Flu id-pressure-regulating valve



No. 613,737. Patented Nov. 8,' I898.

W. P. & R. P. THOMPSON;

FLUID PRESSURE BEGULATlNG VALVE.

(Application filed Feb. 2, 1898.) (No Model.) 2 Sheets-Sheet I.

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No. 6I3,737.

- Patented Nov. 8, I898. W. P. 8.. R. P. THOMPSON.

FLUID PRESSURE BEGULATING VALVE.

(Application filed Feb. 2, 1898.)

2 Sheets-sheaf 2.

(No Model.)

Inveniors .7 (Wu 0 M 'Ma. .4. I Attor zi afi Witnesses;

cams Fetus ca, Puonxurncn WASHXNGTO NlTED STATES \VILLIAM P. THOMPSON AND ROBERT P. THOMPSON, OF PHILADELPHIA.

PATENT OFFICE.

PENNSYL VANIA.

FLUlD-PRESSURE-REGULATING VALVE.

SPECIFICATION forming part of Letters Patent No. 613,737, dated November 8, 1898'.

Application filed February 2, 1898. Serial No. 668 805. (No model.)

To all whom it may concern.-

Be it known that we, WILLIAM P. THOMP- SON and ROBERT P. THOMPSON, citizens of the United States, .residing at Philadelphia, county of Philadelphia, and State of Pennsylvania, have invented a new and useful Im provement in Valves for Reducing and Regulating Pressure of Fluids, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings, which form a part of this specification.

Our invention has for its object certain improvements upon the valves and methodfor reducing and regulating pressure of fluids.

lVe will first describe the invention as illustrated in the accompanying drawings and then specifically point out the invention.

In the drawings, Figure 1 is a vertical sectional view illustrating the preferred form of embodiment of ourinvention. Fig. 2 is a vertical sectional View showing a modified form of embodiment of our invention. Fig. 3 is a front view of pitman H.

A is the inlet from the source of pressuresupply to the valve-chamber, and B the outlet from the valve-chamber. In this valvechamber is a differential valve consisting of the members 0 and D, connected by the valvestem E. The valve member O controls the port 0 and the valve member D the port d. As may be seen from. the construction, the incoming pressure-supply acts upon these two valve members oppositely to force the valve 0 upon its seat and to lift the valve D off its seat. As these two valve members are connected together. by the valve-stem E, the effective surface is the difference in area between the valve member D, the larger, and the valve member O, the smaller. This differential area may be quite small. As may be seen, the valve stem is longer than the distance between the faces of the valve-seats,

and also the lifting or larger valve member D is made cup or dome shaped. The stem is made of a metal whose coefficient of expansion is less than that of the metal of which the valve members are formed. In practice we prefer to make the stem of steel and the valve members of brass. The purpose of this is that under the action of heat the stem expands, and in the ordinary construction when the valve members are lifted from their seats and returned again toward the seat the valve O would seat, while the valve D would not unless this was corrected. With our im proved construction, however, While the valve-stem E will expand, the length of the stem being greater than the distance between valve-seats enables the dome shape of one of thevalves to be of a size sufficient to cause the depending parts to expand sufficient to compensate for the expansion of the stem. The shell carrying the valve-seats is always under the action of the atmosphere, while the stem is directly subjected to the action of the heat. If the stem between the valve shoulders or points of attachment to the valves was only equal, or substantially so, to the distance between the valve-seats under the action of heat, it would be impossible to properly seat both valves. By the use of a stem larger than the distance between valve-seats we can form the dome-shaped member D, which will expandin a reverse direction to that of the stem, and its expansion will compensate for the difference of the expansion of the stem and shell, and as a consequence, the expansion being thus equalized, there will be no difficulty in always seating both valve members.

Projecting from the valve member D is a clip 6.

F is a crank-arm guided in the clip 6. This crank F is fixed on a rock-shaft F. At the opposite end of the rock-shaft is a lever G, I having upon it the movable weight G.

H is a pitman connecting the lever G with the lever H, pivoted at h and having upon it beyond the pivot the weight h.

I is an arm projecting from the lever H between the pitman H and the pivot-point hof the lever H. This projecting arm I rests against a diaphragm-valve J, held in a casing K in the ordinary manner. This diaphragmvalve is in communication with a water-cham= ber L through the medium of a passage Z, hav ing the throttle portion Z. The water-chamber L is in connection with the passage B through the inlet B.

The general purpose of apparatus of this kind is to automatically control the delivery of fluid from a high-pressure supply into a low-pressure servicc-that is, to reduce the pressure-and to control the reduced pressure under variations in the high-pressure supply and preventing the draft from reduced pressure lowering the high-pressu re supply to less than a fixed minimum.

In general the operation is as follows: The weight G is set for the lowest pressure which it is desired to maintain in the boiler-that is, the pressure below which it is not desired under any conditions to allow fluid to pass through the valve from the boiler to the discharge B-while the weight It is set at the highest desired pressure to be reached in the low or reduced pressure system. Initially, when the pressure in the boiler or in the pipe A arises above that to which the weight G is set the valve, by pressure upon the member D, is lifted, and the fluid flows through the passages cl and 0 into the passage 13. From the passage B it also flows through the passage B into the water-chamber L and from thence through the passage 1 and throttlepassage Z to the diaphragm-valve J. When the pressure in the pipe B has risen to the limit set by the weight it, the diaphragmvalve J is operated, which, through the medium of the lever H, pitman H, and connections, again seats the valve members D and C and cuts off the supply. hen the pressure in the pipe B falls below that set by the weight 7t, the diaphragm-valve J is returned and the valve members D and C allowed to again rise from their seat.

The great advantage in this construction is caused by the form of the member D of the diiferential valve D O and by making the valve members D and C of more heat-expansible material than the connectingstem E and making the length of the connecting-stem greater than the distance between valve-seats,

thus making the seating of both members D and C of the differential valve certain.

Having now fully described our invention, what we claim, and desire to protect by Letters Patent, is-

1. A diiferential valve consisting of a plurality of members connected by a stem, the portion of the stem between points of attachment of valve members being of length greater than the distance between the seats of the valve members, the valve members being of greater heat-expansible metal than the stem.

2. A differential valve consisting of a plurality of members connected by a stem, the portion of the stem between points of attachment of the valve members being of length greater than the distance between the seats of the valve members, thelifting-valve member being of greater heat-expansible metal. than the stem.

3. A dilferential valve consisting of a plurality of members connected by a stem, the portion of the stem between the points of at tachment of the valve members being of length greater than the distance between the seats of the valve members, the lifting-valve member being made cup or dome shaped.

4. A differential valve consisting of a plurality of members connected by a stem, the portion of the stem between points of attachment of the valve members being of length greater than the distance between the seats of the valve members, the lifting-valve memberbeing cup or dome shaped, and of greater heat-expansible metal than the stem.

Signed by us, at Philadelphia, this 26th day of January, 1898.

WILLIAM P. THOMPSON.

ROBERT P. THOMPSON.

Vitnesses:

WM. WAGNER, J12, II. M. TSCI-IUDY. 

